On Tue, Feb 21, 2012 at 10:00 AM, Michael Dickens <address@hidden>
On Feb 21, 2012, at 9:44 AM, Tom Rondeau wrote:Ah; yes. That makes sense. My mind is thrashing with multi-thread dilemmas, not signal processing, right now.
> It's because with the larger bandwidth, the subcarriers, too, have a larger bandwidth. The coarse frequency correction is only set to look at so large an offset based on a number of subcarriers (+/-5 or 10), so now with the same frequency offset, 5 (or 10) carriers is a larger frequency span to check.
>> 1 MHz off at 5 GHz is 200 ppm (yes?). IIRC a reasonable spec on these boards is 5-10 ppm. So, > 10x off the spec? I doubt it. My guess is it's something in GNU Radio that wasn't fixed when the benchmarks were transitioned from gr-usrp* to UHD.
> I think this is a known problem with the XCVR that has been fixed. Make sure you have the most up-to-date master branch of both the UHD and GNU Radio.They were both the most recent as of yesterday. I'll update right now & see if that helps, but I'm doubtful since none of the commits since yesterday seem to impact the behavior of the XCVR. I'll also remove any cruft in /usr/local before re-installing. More later. - MLD
No, this would have been fixed weeks/months ago, so updating today won't help.
Are you seeing the 1 MHz offset when you use the uhd_siggen.py? Or is it just with the OFDM transmitter?